Lesson: Kinetic Friction

Block 2 slides along a frictionless table as block 1 falls, as shown. Both blocks are attached by a frictionless pulley. Assume that both blocks start at rest and that the pulley has negligible mass. The mass of Block 1 is and the mass of Block 2 is . Find the speed of the blocks after they have each moved 2.0 m.

A sled starts moving from rest at the top of a snow-covered slope that is inclined at angle below the horizontal. After sliding 63 m downward along the slope, the sled’s speed is 8.7 m/s. Calculate the coefficient of kinetic friction between the runners of the sled and the slope’s snowy surface.

A student is moving a mini-fridge that has a mass of 27 kg. The mini-fridge slides at constant speed downward along a slope that is inclined at below the horizontal. While the mini-fridge slides down the slope, the student is pushing it with a 22-N force acting parallel to the slope in the opposite direction to the fridge’s motion. What is the coefficient of kinetic friction between the mini-fridge and the surface of the slope?